Glazed ceramic ware and method of making



Patented Dec. 15, 1936 2,063,953 GLAZED CERAMIC WARE AND METHOD OF MAKING Gordon R. Pole, Florence, Ala, assignor to Tennessee Valley Authority, Wilson Dam, Ala, a corporation of the United States i No Drawing. Application February 27, 1936,

Serial No. 66,063

9 can... (01. 25-151) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) This application is made under the act of Run No. 3. Glazed by volatilizing phosphorus March 3, 1883, as amended by the act of April 30, pentoxide in kiln.

1928, and the invention herein described, if pat- Run No. 4. Glazed by alternate salt glazing ented, may be manufactured and used by or for and burning yellow phosphorus in kiln. the Government for governmental purposes with- I The test pieces were examined for the brightout the payment to me of any royalty thereon. ness and thickness of the glaze produced with This invention relates to a new glazed ceramic the following results: ware and a process for making the same.

One of the objects of this invention is to pro- R an z gy a salt glazing vide a ceramic ware with an improved finish.

Another object of this invention is to produce an improved vapor glaze on ceramic ware. Other My Minn objects of this invention include the provision for. a means for glazing ceramic ware that is difficult g ggfi g 685% ggggfiglg gz to glaze by the ordinary salt glazing method. High lime, 4% mm, thin glam Ceramic ware, such as brick,.sewer pipe, stonefl alumina 49% D11,

ware, telephone conduit, and tile, is ordinarly vapor glazed by contacting the ware, heated to Run No. 2.-Glazed by burning yellow phosglazing temperature, with a gaseous mixture car'- phorus in kiln 0 rying vaporized sodium chloride. The quality of the glaze obtained depends largely on the compo- Ceramic body Description olglue sition of the molded ware with all other conditions being favorable. Compositions which are high in may only Bflght'tmn gm silica yield a satisfactory glaze with sodium chlo- High silica, 68.5% Bright, thin glaze ride, while those compositions which consist of g g? 40% clay only, or which are comprised of high lime or high alumina content, yield correspondingly poor Run Na 3' Glazed by mutating phosph glazes.

I have discovered a new article of manufacture kan 9 consisting of a ceramic ware which has been glazed with phosphorus pentoxide and a method M WW for making the same by contacting the ceramic ware, either unglazed or previously salt glazed, p r Dulhthlnslm 'with a gaseous mixture containing phosphorus gig fif'f fifififigfi pentoxide, while maintalmng the same at a. glaz- Blah alumina, Dull. i el ing temperature.

One example of the operation of my process and Run No. 4.Glazed b1! alternate salt glazing and the product resulting is given with a variety of burning yellow phosphorus in kiln 4o raw materials and compared with the usual processes' of salt glazing and the product obtained gmmicbody Mpg thereby: Four ceramic bodies of the following composi- Clay only Bright, thick m tions were made into the test pieces, High sillca, 68.5% Bright, thick glass 7 High lime, 4% Bright, thick glaze Body No. 1 Clay only 56% $102 37% A1203 alumina, n'ight'tmck EM Body No. 2 High silica 28.5% giO 26%Al 0, 1,333; f; E5 5 3%,, X It is evident that there are numerous factors Y which will influence conditions for the most satis- These four ceramic bodies were vapor glazed at factory operation of my invention, the actual 50 Cone No. 6 (1230 C. approximately) by the follimits of which cannot be established except by a lowing methods: detailed study ofeach set of raw materials and Run No. 1. Glazed by regular salt glazing the intermediate and finished products involved. method. Even though glazing with phosphorus pentoxide Run No. 2. Glazed by burning yellow phos- 'may improve the glaze on those waresv which may phorus in kiln. be satisfactorily glazed by the usual methods,

using ordinary salt, sodium chloride, it is preferred to use the phosphorus pentoxide in the glazing of those wares which are diillcult, or practically impossible to glaze, by the use of ordinary salt, such as wares which have a high lime or high alumina content. Such wares may be glazed by the use of phosphorus pentoxide alone or after a preliminary salt glaze produced in the usual manner. In some instances the phosphorus pentoxide glazing may be followed by a final salt glazing.

The gaseous mixture containing phosphorus pentoxide and suitable for glazing with the material may be obtained by any convenient means, such as, by the partial or total oxidation oi phosphate reduction furnace gas, by the oxidation of elemental phosphorus or by the volatilization of phosphorus pentoxide. The amount of the phosphorus pentoxide required will depend upon the composition and the surface or the ware to be glazed. The operation of a 30 foot down-draft sewer pipe kiln given below will serve to further indicate the method of operation and the amounts oi glazing materials required. One round or salt means to lbs. of sodium chloride, distributed equally to each flre box and oneround of phosphorus pentoxide means 25 to 100 lbs. of phosphorus pentoxide, or its equivalent, distributed equally to each fire box. The ware to be glazed is placed in the kiln, brought to the proper temperature for salt glazing and contacted with a gaseous mixture containing the active glazing agent in any one of the sequences outlined as follows:

1. One or more rounds of phosphorus pentoxide.

2. One or more rounds of phosphorus pentoxide, and one or more rounds of sodium chloride.

3. One or more rounds of sodium chloride, and one or more rounds of phosphorus pentoxide.

4. One or more rounds of sodium chloride, one or more rounds of phosphorus pentoxide and one or more rounds of sodium chloride.

The kiln is operated throughout in substantially the same manner currently used in the salt glazing operation and after the final glazing operation the kiln is cooled in the usual manner.

It will be seen, therefore, that this invention actually may be carried out by the modification of certain details without departing from its spirit or scope.

I claim:

1. Process for making glazed ceramic ware,

which comprises, burning a phosphate reduction furnace gas to form a gaseous mixture containing phosphorus pentoxide. and contacting a glazed ceramic ware with the gaseous mixture containing phosphorus pentoxide. while maintaining the ware at a glazing temperature.

2. Process for making glazed ceramic ware. which comprises, burning elemental phosphorus to form a gaseous mixture containing phosphorus pentoxide, and contacting an ungiazed ceramic ware with the gaseous mixture containing phosphorus pentoxide, while maintaining the ware at a glazing temperature.

3. Process for making glazed ceramic ware, which comprises, contacting an unglazed ceramic ware with a gaseous mixture containing sodium chloride, while maintaining the ware at a,

glazing temperature; and contacting the salt glazed ceramic ware with a gaseous mixture containing phosphorus pentoxide. while maintaining the ware at a glazing temperature.

4. Process for making glazed ceramic ware,

5. Process for making glazed ceramic ware,

which comprises, contacting a; glazed ceramic ware with a gaseous mixture containing phosphorus pentoxide, while maintaining the ware at a glazing temperature.

6. Process for making glazed ceramic ware, which comprises, contacting a ceramic ware with a gaseous mixture containing phosphorus pentoxide, while maintaining the ware at a glazing temperature.

'7. A glazed ceramic ware, consisting of, an 7 unglazed ceramic ware which has been glazed with salt and phosphorus pentoxide.

8. A glazed ceramic ware, consisting of, a glazed ceramic ware which has been finally glazed with phosphorus pentoxide.

9. A glazed ceramic ware, consisting of, 9. ccramic ware which has been glazed with phosphorus pentoxide.

GORDON R. POLE. 

